It has been found that positive pressure ventilation of a structure sustaining an internal fire has many advantages. The use of positive pressure ventilation techniques usually results in removing the smoke in a fraction of the time previously required. The faster evacuation of smoke reduces smoke damage. Most importantly the rapid removal of the smoke and cooling of the area dramatically increases fire fighting safety. The firemen have considerably greater visibility to see and comfort within the burning structure. They are then more able to rapidly locate the hot spots without having to crawl on the floor. Also, the speedy removal of smoke and the replacement with cool moist air allows breathing apparatus to be removed sooner. Overall physical stress of fire fighters is reduced with less stress related injuries. This all results in greater fire fighting productivity.
To be able to obtain the above advantages a lightweight, hand portable positive pressure blower is required that can be easily maneuvered into position in front of an opening to a burning structure. Such a blower is disclosed in U.S. Pat. No. 4,906,164. The blower disclosed therein has substantial benefits in producing a positive ventilating pressure for fire fighting. The disclosed blower is easily transported and stored on a fire fighting vehicle.
It has been found that the addition of a water mist to the airstream of a positive pressure blower obtains benefits not realized with dry airstreams. The addition of water to the airstream has the effect of drastically cooling the airstream. This has the very noticeable benefit of increasing the comfort and safety of the fire fighters and victims in the airstream. Further, the moisture in the air has the potential of extinguishing fire without causing water damage. Still further, small droplets of water in the moving airstream collect particles of combustion and smoke, carrying both away from the heat source, increasing visibility and breathability of air within the structure.
A misting fire ventilation blower is commercially available through the Hale Fire Pump Company of Conshohocken, Pa. The device is sold under the Trademark, "TYPHOON". It is a water turbine driven positive pressure ventilation system with an on-demand water mist injector. The injector nozzles are placed on the blower at locations directly upstream of the blower blades. The injected water must pass through the rotating blades before being driven into the discharged airstream. Many of the droplets strike the several blades and are thrown by centrifugal force onto the surrounding shroud, only to drop off onto the ground surface. The water droplets that do not collect on the blower shroud move by centrifugal force of currents in the airstream to the outward perimeter of the airstream, where many gather into large droplets and precipitate out of the airstream before reaching the fire. The apparatus therefore calls for an amount of water (up to 8 gallons per minute) that is excessive. Still, the water that does remain airborne has the desired effect of cooling the airstream and reducing ambient temperature.
A need remains to obtain a positive pressure ventilation blower and water misting system that will minimize water usage while maximizing the water content of the ventilator airstream and likewise maximizing the attendant benefits to the firefighters, victims, and the involved structure.
One of the objects and advantages of the present invention is to provide a compact, hand portable positive pressure blower that can be easily stored on a fire fighting vehicle and that has the capability of producing an airstream with an optimum water content in the form of mist and vapor that will facilitate maximum cooling of ambient air, and to carry the moisture laden air fully into and through a desired area involved in a fire.
A further object is to provide such a ventilator that will minimize the amount of water required for such air cooling and thereby minimize water damage to adjacent structures.
A still further object is to provide such a ventilator that will occupy only a single water supply hose at minimal operating pressure.
A further object of this invention is to provide such a blower which does not require the presence of an attendant during operation.
These and other objects and advantages will become apparent upon reading the following description of a preferred embodiment of this invention.